At the time of cutting sheet members, the sheet members are fixed by vacuum suction or the like, and the sheet members are cut by a knife or a round blade. According to the disclosure of Patent Publication 1 (Japanese Laid-Open Patent Publication No. 9-103991, U.S. Pat. No. 5,791,216), a sheet member is cut efficiently using both of a circular blade and a knife appropriately. The blade width of the knife is smaller than that of the round blade. According to the disclosure of Patent Publication 2 (Japanese Laid-Open Patent Publication No. 48-74683, U.S. Pat. No. 3,780,607), at the time of cutting a sheet member made of material having a low melting point such as vinyl chloride, since a cutting blade is not pulled out from the sheet member, the frictional heat is released through the cutting blade, and fusion of the sheet member is prevented. That is, if fusion of the sheet member occurs, problems may occur. For example, it happens that the sheet member is adhered to another sheet member, and patterns such as a printing pattern disappear. The surface of the sheet member may become rough, and the cutting line may become unclear. Therefore, the cutting blade is used for releasing the heat to prevent fusion.
However, at the time of cutting stacked sheet members made of material having low permeability such as vinyl chloride or synthetic leather, the upper sheet members are not sufficiently fixed by vacuum suction. The upper sheet members may warp, or may slide on the other sheet members undesirably. Thus, it may not be possible to cut the sheet members accurately.